Idk but the German production line just has a different feel to it, all have gloves,matching uniforms and a body language that says, "excited to be working here building bimmers". The guys in this vid didn't seem that confident or something.

I think for the SA plant workers, if it comes to it, treasure their jobs even more than the Germans. One just has to compare the unemployment rates of both countries.
Notice the "No Vacancies" sign at the plant's entrance, it is a constant reminder that if u fail at ur job, there are hundreds lining up outside to replace u. The filming of the video I think gives them more pressure in this sense.
I've been to plants in Japan, & if u compare German workers with the Japanese, the Germans seems to be on holiday.